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When I appear on radio and am talking about climate change, I often get the same questions over and over.
- Is the climate warming?
- If so, is human behavior an important factor for causing that warming?
- How much does the sun influence climate change?
- Is the ozone hole linked to climate change?
The truth is that, right now, no one can really answer any of these questions with any certainty. While a large majority of climate scientists might be convinced the Earth is warming and that human activity is causing this warming, the public has great doubts about these claims, partly because of the untrustworthy behavior of many of these climate scientists and partly because the science itself is often confusing.
We simply don’t yet have enough data. Worse, much of the data we do have is tainted, unreliable because of the misconduct and political activism of the very climate scientists who are trying to prove the case for man-made global warming.
Two new papers, published today in Geophysical Research Letters, add some interesting but small data points to this whole subject.
The first, “The persistence of solar activity indicators and the descent of the Sun into Maunder Minimum conditions,” takes a close look at the just ended long, deep, and extended solar minimum in order to compare it to the beginning of the Maunder Minimum of the 1600s, when there were no significant sunspots for six-plus decades, to see if this can give us clues on whether the sun is about to enter another such Grand Minimum.
The scientists conclude that it should be possible to predict the onset of a Grand Minimum, and that the sunspot numbers of the just completed minimum suggest that we might very well be at the start of one.
The current declines in peak and mean [sunspot numbers] are the largest since the onset of the [Maunder Minimum] and exceed those around 1800 which failed to initiate a [Grand Minimum].
The scientists do note however that the data could also support us entering a period of subdued maximums similar to the Dalton Minimum of around 1800, when two succeeding solar maximums produced sunspots but at much reduced numbers.
Either way, during both the Maunder and Dalton minimums there is strong evidence that the Earth’s climate got colder. Whether it was the sun’s behavior that caused this cooling remains an area of debate among scientists. Recent results from CERN provide strong evidence that the sun did influence this cooling, and might very well produce cooling again if the sun dips into another Grand Minimum.
Some thoughts about two of the authors of this paper. I am very familiar with the work of Lockwood and Owen, having read numerous papers by both on the subject of the solar cycle. Their work is consistent and robust, and rarely delves into grey areas where models take precedent over data. Instead, these climate scientists focus on observational data, and what that data tells us.
The second paper, “Observed and modelled record ozone decline over the Arctic during winter/spring 2011”, takes a look at the unprecedented large ozone hole over the Arctic during the cold 2011 winter, when the temperatures in the stratosphere over the North Pole were colder than in recent years. The paper compares the predictions of several computer models with actual satellite data, and concludes that the models are reasonably good at predicting ozone layer levels over the Arctic based on temperature. For example, during the warmer winter of 2010 both models and data showed higher ozone levels. The data and models thus suggest that
The interannual variability of column ozone over the northern polar region is, as expected, highly correlated with the corresponding year-to-year variability of the seasonally-averaged temperatures in the lower stratosphere.
In other words, the ozone hole over the Arctic is due to annual temperature changes. Colder weather will increase the size of the ozone hole.
What do these two papers mean for climate change? Not a lot, to be honest. What they provide us are two small data points. The first is that the sun might be entering a Grand Minimum. Whether that will cool the Earth remains a scientific question, one that scientists are only now trying to answer.
The second data point is that the northern hemisphere ozone hole is directly tied to seasonal and year-to-year temperature variations in the stratosphere. Whether the cooling during the past winter had anything to do with the sun’s deep minimum is completely unknown. According to the second paper, this stratospheric cooling is related to climate warming:
[T]he stratosphere is predicted to cool, in parallel to the warming of the climate at the Earth’s surface and the short and long-term processes that determine polar stratospheric temperatures in winter are complex [Zerefos et al., 1994; Rex et al., 2006]. [emphasis mine]
I emphasized the second part of the sentence above because it is what tells us the true state of the science. Scientists really don’t understand yet what is going on, and the prediction that global warming will cause stratospheric cooling remains unreliable. Such cooling could just as well have been caused by increased cloud cover caused by increased cosmic ray impacts caused by an inactive sun, as suggested by the CERN results noted above.
Stay tuned. It will probably be at least another decade before our understanding of the climate grows sophisticated enough for us to answer these questions.